Search Documents

By D A. McCallum

With depth, many gold ores become sulfidic with minerals such as pyrite, pyrrhotite and arsenopyrite becoming prevalent. In addition, many underground gold mines use tailings backfill to bind and store the waste. In these cases, acid mine drainage (AMD) can become an issue. One approach to the control of AMD is desulfurisation whereby the sulfide minerals are removed prior to disposal. Four sulfide tailings samples, representing different ore types and gold and base metal operations, were selected for assessment and testing using simple physical beneficiation techniques. The aim was to determine the extent to which mineral processing methods were suitable for separating sulfides from non-sulfides and for extracting potentially marketable by-products from the tailings. In order to streamline the testing procedure a simple diagnostic separation technique was developed to enable quick screening of bulk sulfide tailings for suitability for reprocessing. The testing procedure involved detailed characterisation and a sequential set of testing regimes based on simple unit processes including water washing, classification, gravity concentration, magnetic separation and bulk flotation. The preliminary test results indicate each unit process can play an important part in producing effective sulfide/non-sulfide separations and in generating useful by-products from the tailings. Potential valuable products identified include coarse, benign silica sands, bulk iron sulfide products rich in pyrite and/or pyrrhotite, high-grade iron products (magnetite) low in silica, low-volume bulk sulfide concentrates and low-grade molybdenite and talc products. The work presented shows how sulfide tailings can be viewed as a resource rather than a waste stream, and identifies a pathway for developing a more sustainable approach to the environmental management of sulfide tailings for the future.

Jan 1, 2007

By Hans Perlid

In the handling of emulsion explosives pumping is a key operation. A number of serious accidents has shown that pumping can be a risky operation and should be carefully considered and investigated. This is the background behind a series of pump tests carried out by NITRO NOBEL.

Jan 1, 1996

The main factors which influence disposal of mine waste under New Zealand conditions are identified and discussed: namely, geological conditions which produce soft weather-sensitive waste, wet and cold winters which affect productivity in such waste, elevated seismicity which affects stability and the need for water rights which involve public participation. The waste disposal scheme for the Martha Hill Project is described, thereby illustrating how these factors influence the planning of a current mine strippings and tailings disposal scheme.

Jan 1, 1986

By M. Troyer

A coal shuttle car equipped with a pulsed laser optical ranging system to provide guidance for an automatic steering system was tested in production coal mining. Test results are presented for the two mines where testing took place, and some operator's reactions are included. Automatic steering control keeps the car cantered in an entry, and automatic turns are made at intersections as signaled by the operator. All other controls-tram, conveyor, brake, etc, remain manual and require operator control. Complete override of steering while in the automatic mode is retained by the operator, who may grab the steering wheel at any time and turn in opposition to the automatic signal by applying about 10 foot-pounds of torque.

Jan 1, 1976

By Lyon R. J P

The quartz-cassiterite-wolfram veins at the Aberfoyle Tin Mine, north-eastern Tasmania, form a sheeted zone about 200 ft. wide and 1,600 ft. long in slightly contact metamorphosed shales, slates and greywackes, and are associated with a cupola of aplitic granite whose top is about 1,050 ft. below the present surface. Economic mineralization persists from the surface down to a vertical depth of 1,050 ft. to 1,100 ft., dying away in the vicinity of the cupola. Down to the 9-level there is a progressive increase in wolfram content of the veins, and a decline in cassiterite content, with increasing depth.The veins are banded or zoned, with a seivedge of muscovite on the wall. Cassiterite, wolfram and sphalerite occur inside the selvedges, projecting into a core of quartz of varying width. Other sulphides form the central part of some narrow veins, or occur as clots in the quartz. The general sequence of deposition of the ore minerals was: (1) cassiterite, wolfram; (2) arsenopyrite, pyrite, molybdenite; (3) pyrrhotite (in part); (4) blende-group minerals-chalcopyrite, sphalerite, stannite, pyrrhotite (in part)-as solid solutions; (5) galena, tetrahedrite, matildite, native bismuth, scheelite; (6) marcasite and secondary pyrite, magnetite and hematite. The sequence of deposition of the gangue minerals was: (1) fluorine-bearing minerals-muscovite topaz, apatite, triplite, fluorite-more or less contemporaneous with the cassiterite and wolfram;' (2) quartz-contemporaneous with the earlier sulphides; (3) carbonates--contemporaneous with the later sulphides. The stages overlapped somewhat.The composition of the sphalerite and heat treatment experiments with the solid solutions indicate that the blende-group sulphides were deposited at about 6000 C., and cooled rapidly, so that unmixing of the solid solutions was arrested. This accords with the likelihood that the country rock temperature was not above 2000 C. Annealing experiments at between 3500 C. and 6000 C. led to further precipitation from solid solution at the lower temperatures, and to significant segregation by solid diffusion within, a week, indicating that both deposition and cooling of the ore were rapid processes-completed in a matter of days. Since the mineralizing solutions must have lost some heat during...

Jan 1, 1957

By Charles L. Kimbell

The year 1980 on the whole was not a good year for the world's mineral industry. The general upturn of activities in 1979 after a rather poor 1978 showing was not maintained with a number of key measurement standards showing downturns. Most notably, the world's steel and petroleum industries recorded significant reductions in output, the former in response to markedly lower demand levels and the latter partly in response to lower industrial consumption owing to general economic conditions and partly owing to successes in campaigns for the reduction of energy use in general and petroleum product use in particular among major importing nations that were feeling the trade balance pinch of ever-higher oil prices. During 1980, a number of political events-some international in scope, some confined to single nations-had significant influence upon world mineral industry activities and mineral commodity supplies, and other political happenings had the potential to significantly affect the industry in future times.

Jan 1, 1982

The work to be described is part of a comprehensive research on the influence of impurities on the properties of lead. The author had previously compared an electrolytic lead containing less than 0.002% total impurities with a commercial lead containing 0.008% impurities (excluding oxygen) and had shown that the former recrystallised more readily than the latter under the same conditions of cold work and annealing. This difference in properties was attributed to the difference in purity. Electrolytic lead containing only 0.0005% total impurities has been prepared and cast in vacuo. Some interesting effects have been obtained by working and annealing this lead, and by adding silver to it. The preparation of this lead, and the effects obtained thereon, are described in this paper. Thepaper is divided into the following sections:(I) Preparation of electrolytic lead.(II) Vacuum Casting.(III) Effect of Cold, Work and Annealing on two Electrolytic Leads, having 0.002% and 0.0005% Total Impurities respectively.1 Research Fellow, Dept. of Metallurgy, University of Melbourne.2 Proc. Aust. lnst. Min. Met., 1932, 87, 145.

Jan 1, 1934

By Michael S. Zhdanov

One of the major problems of mineral exploration is the ability to reliably distinguish between uneconomic mineral deposits and economic mineralization. While the mining industry uses many geophysical methods to locate the mineral deposits, until recently, there was no reliable technology for mineral resources identification and characterization. The main goal of this project is to develop a new geophysical technique for subsurface material characterization, mineral exploration and mineral discrimination, based on electromagnetic methods. The proposed new technique is based on examining the spectral induced polarization effects in electromagnetic data using the modern distributed acquisition systems and advanced methods of 3-D modeling and inversion. The recovered parameters of the relaxation model will be used for the discrimination of different rocks, and in this way will provide an ability to distinguish between uneconomic mineral deposits and zones of economic mineralization using geophysical remote sensing technology (Zonge, 1976). The proposed research and development is undertaken using multi-partner collaboration between the University of Utah, four major mining companies, Kennecott Exploration, BHP Billiton World Exploration Inc., Placer Dome Inc., Phelps Dodge Exploration, and Zonge Engineering Inc., which is equipment manufacturer and service provider to the mining industry. The multi-partner collaboration between the academic institution, the University of Utah, and mining industry helps to identify the appropriate mining target and conduct the field experiment for practical demonstration of the developed new technology, which is an important part of the this project.

Jan 1, 2005

By S. Kitamura

In recent years, the amount of ferritic stainless steel production has increased. However, the rust formation by the salt spray test was pointed out in the past. At the centre of the circular rust zone, pitting corrosion where water-soluble nonmetallic inclusions were embedded was observed. These inclusions originated from the suspended refining slag and consisted of multi-phase oxides and sulphides. By the experiments and thermodynamic consideration of the water-solubility, not only CaO or CaS, but also lime rich calcium-aluminates or calcium-silicates have shown large water-solubility. The composition of oxide phase in the inclusions was almost the same among the samples from molten steel, slab, or cold rolled sheet. On the contrary, CaS was clearly observed around the oxide in the sample of cold rolled sheet, although it was not found in the molten steel or slab samples. The enrichment of sulphur occurred from the desulphurization reaction of the suspended slag particles in the molten steel and also occurred from the diffusion of sulphur to the oxide inclusions during the heating of the slab. The optimization of refining slag composition has lead to produce the ferritic stainless steel without rust formation. Keywords: stainless steel, rust, calcium aluminates, calcium sulphides, water-solubility, refining slag, composition control of inclusions.

By Joseph Clare, Elizabeth Anderson, Mike McGinley, Ron Hines, Judy Cochran

The South Lake Union Pipelines contract for King County Wastewater Treatment Division and Seattle Public Utilities in Seattle, Washington included three 1.8 m (72-in)inside diameter microtunneled pipeline segments totaling about 793 m (2,600 lf).Tunnel alignments were within street right-of-way of heavily traveled urban roadways. Project challenges recognized in the design included: high groundwater levels; contaminated soil and groundwater; variable soil conditions, including fill; and timber piles and other obstructions remaining from historic land uses. The tunnels were built using a Lovat MTS Microtunneling machine, beginning in spring 2003. Conditions encountered during construction presented additional challenges beyond those anticipated in the design process, and were successfully addressed by the owners, designer, and construction management consultant all working with the contractor. Problems included highly variable soil conditions, cracking of reinforced concrete pipe joints during pipe jacking, a timber pile trestle uncovered during shaft construction, and obstructions encountered in the second and third microtunnel runs.

Jan 1, 2005

By E. Contestabile, R. von Rosen, R. Guilbeault, R. Fouchard, P. Lightfoot

In August 1998, a truck loaded with 18 tons of blasting explosives, including over 13 tons of ANFO, left the road near Walden, Ontario. The crash caused a fire; approximately 30 minutes later a large detonation occurred, causing substantial damage to the roadway and local property. Although nobody was injured in the explosion, the consequences of a similar incident in a heavily populated area could have been catastrophic. Following the Walden incident, Transport Canada and Natural Resources Canada embarked on an extensive experimental program to determine the cause of the detonation. This paper describes part of that experimental program, designed to understand better the thermal decomposition of ANFO.

Jan 1, 2003

By J. Wickens

Haile Gold Mine is located near Kershaw, South Carolina, approximately 50 miles south of Charlotte, North Carolina. Gold was first discovered at the site in 1827, and the property has been through several operating periods since. The relatively low grade and refractory nature of the deposit has been a challenge for efficient processing since the start of mining on the property. Early processing techniques included gravity separation and barrel chlorination. The last operation employed heap leaching in 1985 through 1992. After being closed and reclaimed for over 20 years, the property is poised to re-open and produce once again. In this chapter of the Mine?s legacy, flotation and ultra-fine grinding will be employed to achieve economic extraction of gold and silver from the pyrite. This paper briefly reviews some of the mine?s history, the metallurgical testing, the flowsheet and discusses design considerations. KEY WORDS: process plant, flash flotation, leaching, SMD, stirred media detritor

Feb 27, 2013

By M. K. Pelser

The purpose of this paper is not so much to provide a scientific study of the selection process for the perusal of other psychometrists or industrial psychologists?the purpose is to provide line management with a practical, relatively user-friendly guide to fair and scientific selection. The main areas that are to be covered are: ? Why fair and scientific selection? ? Job analysis ? The job requirement?selection technique circle ? Assessment centres in the mining industry?the Tavistock Collieries Ltd experience. Why fair and scientific selection? Seen from a line manager?s perspective, fair and scientific selection should be pursued for two main reasons: ? to remain within the ambits of the law ? to maximize the probability of selecting the potentially most productive and efficient candidate for the job.

Jan 1, 1997

By A. More, J. Bullón

Metal casting is one of the most important operations in ferroalloys factories. After the tapping of the furnace and the depuration of the metal, the preparation for customers with cooling, crushing and sizing begins. In total production costs, this contains around 8 % of the total cost of the metal, depending on the value of the fines and other important parameters. From an investment point of view, this represents around 20% of the total capital for a new furnace. Casting onto a water-refrigerated copper plate is not new for molten metals. In steel, continuous casting machines are normal in every factory. Water granulation casting exists at some ferroalloys plants. However, the majority of plants and production technology still use the technology of lumping, crushing and sizing. This technology is time consuming, produces fines and requires a relatively large work force. In 2001, Ferroatlantica put into operation a new water-cooled copper casting-machine, which seems to be a very convenient solution to solve all these problems. It is in operation at a silicon factory; the same place where the new ELSA electrode was developed for silicon metal production. This paper describes our experiences using it.

Jan 1, 2004

By J. A. Herbst

During the last decade it has been established that conventional flotation control strategies based on classical control theory result in significant increases in grade, recovery, and operating-cost savings. In the current report a description of an advanced model-based control philosophy is presented. The derivation and verification of a simplified flotation model is described. The implementation of a Kalman filter for estimation of unmeasured variables for input to controllers is discussed. Several control strategies using the model-based approach are described, emphasizing the nonlinear nature of the flotation plant. Expected trends in the implementation of such model-based flotation control strategies in the future are discussed.

Jan 1, 1986

By Don Kay

A two year study into the effects of coal mining induced subsidence on cliff lines was undertaken by the Department of Mineral Resources with the support of a grant under the National Energy Research, Development and Demonstration Program. A new monitoring technique, using an Electronic Distance Meter and acrylic reflectors attached to the cliffs, provided safety for the surveyors and extensive and accurate three dimensional displacement data on the movement of the cliffs as they were being undermined. The study report included many graphs showing the measured vertical and horizontal displacements, differential subsidence, tilts and strains and included analysis of these movements with various parameters, such as, seam thickness, depth of cover and distances between the reflectors, longwall face and the edge of the chain pillar. Some of these graphs are presented in this paper and could be used, with caution, to predict subsidence movements around other cliff lines, after allowing for differences in geology and mining layout. A mechanism is suggested as an explanation for the observed high horizontal movements around the cliff lines. Sixteen percent of the overall lengths of cliffs that were undermined during the monitoring study fell and the contributions of various factors that appeared to influence the cliff falls are discussed. It is concluded that no single factor dominated as the major cause of the cliff falls and, often, many factors combined to cause cliff face instability.

Jan 1, 1992

By R. B. Fisher

This report gives the results of mineralogical research on the Nicaro (Cuba) nickel ores and plant products. These studies were made under a cooperative agreement with the General Services Administration (GSA) of the U. S. Government. The purpose of the investigation was to obtain fundamental data that would be useful to other GSA contractors concerned with the Nicaro ores in their research on reduction roasting, leaching, and other phases of the project; and to the metallurgical staff of the Nicaro plant in Cuba. The overall objective of the combined research was to provide data to accomplish metallurgical improvement in the operations of the U.S. Government-owned plant at Nicaro, Oriente Province, Cuba. Particular emphasis is placed on improving the recovery of nickel from the ores and on the possibility of recovering other valuable constituents, especially cobalt. This study presents the physical and chemical characteristics, mineral associations, differential thermal analyses in controlled atmospheres, and X-ray studies of the ores and plant products. The nickel ores, serpentine and laterite, were from the Ramona-Lama Mulo and Ramona ore deposits. Serpentine ore consisted of serpentine-group minerals, basic iron oxide, magnetic iron oxides, chromite, olivine, enstatite, anthophyllite, cryptocrystalline quartz, wad, and a trace of calcite. This ore contained 1.6 percent nickel, 0.05 percent cobalt, 0.86 percent chromium, and 17.4 percent iron. Laterite are was composed principally of goethite with some altered serpentine, quartz, chromite, wad, magnetite, maghemite, and hematite. It carried 1.3 percent nickel, 0.11 percent cobalt, 1.9 percent chromium, and 48.4 percent iron.

Jan 1, 1959

By Paul Zick

The Port Authority of Allegheny County North Shore Connector (NSC) Project involves TBM excavation of twin 690 m (2,240 lf) precast segment lined light rail tunnels through soil and rock under the Allegheny River and a narrow, downtown city street. The $435 M project is funded 80% ($348 M) by the Federal Government, 17% ($72.5 M) by the State of Pennsylvania and 3% ($14.5 M) by Allegheny County. Along the tunnel alignment are a historic building on shallow foundations, modern buildings on deep foundations, and one building constructed directly over the alignment. The project includes construction of twin 369 m (1200 lf) cut and cover concrete box tunnels and an underground station shell. This paper provides an overview of general site conditions, current project status and construction challenges for the Twin Tunnels and North Shore Light Rail Station.

By T. Peters, W. C. Ferguson

"Shebandowan is about 600 miles west of Sudbury and 50 miles west of Thunderbay close to the trans Canada highway. Shebandowan Lake is about 38 miles long. The ore body is located between No. 1 and No. 2 shafts at the lower end of the lake. The economic mineralization lies between 200 and 2000 feet below. Years ago development of this ore body would probably have entailed draining the lake and using the open pit method to mine the ore.The water of Gold Creek which flows into Lake Shebandowan is representative of all local waters and is very close to rain water in purity. It is obvious that any industrial water discharged would have a measurable impact on the local water. The dissolved solids content is low and consistent with what is normally found in northern Ontario.A Koepe headframe is the only visible evidence of the mine from the lake. The Koepe headframe is esthetically pleasing and quiet in operation. The structure is of concrete to control noise. Noise from ore dumping is controlled by dumping underground to an ore pocket 400 feet below the surface. A 3600 foot conveyor belt carries the ore underground to the mill and is out of sight of the lake and the cottagers. The main objective to all our environmental efforts has been to preserve the natural beauty of the region. The mill is housed in a conventional metal-clad-siding building painted in esthetically pleasing colours. A single service building houses warehouse, dry storage and offices. The area surrounding the mill and service building is paved or grassed and drainage from this area is collected and pumped to the tailings area. Air intake silencers are installed on the compressors which are mounted at the back of the mill. Sound measurements taken on the lake indicate that noise suppression is excellent."

Jan 1, 1975

Mineral formations, accumulated during technogenic activities greatly influence an economic and ecological situation in the Kola North. On the one hand, the dumps from extraction of mineral resources, tailing ponds of beneficating plants, ash dumps, wastes of metallurgical and mechanical engineering productions destroy the regionÆs environment and require taking certain measures and costs to bury or protect from weathering, oxidation, etc. On the other hand, technogenic mineral formations contain a lot of valuable scarce components. The amount of solid wastes increases annually, causing damage to ecology and economy. Researches conducted in recent years showed a possibility and economic expediency of comprehensive processing of wastes from different enterprises in Murmansk region and their use for production of new competitive commodity output, possessing high consumer properties. Thus, involving mineral wastes from Khibiny apatite deposits into hydrometallurgical industrial processing provides the basis for setting up a large beneficating-metallurgical complex. In this case ores and wastes from other deposits on the Kola Peninsula, containing titanium, rare, rare-earth and other valuable elements, may be involved into processing. Establishing such a complex will allow to organise a deep processing of natural resources, utilise some production wastes, improve ecological security and supply production with competitive output. Expanding the complex implies not only involving new mineral raw material into processing, but mainly deepening raw material processing, maximum utilisation of local natural resources and obtaining a wider variety of prime products.

Jan 1, 2002